In the electrophotographic image forming device, an image forming device member formed of a conductive polymer material is used in the shape of a roller, a blade, and the like for charging, for developing, for transferring, for toner supplying, for cleaning, and the like.
As the conductive polymer material used for such an object, a material which has low hardness, does not contaminate a photoreceptor and a transfer material, and does not fuse with a toner is required, and thus a polymer elastomer and a polymer foam having rubber elasticity are used.
As a material configuring the polymer elastomer and the polymer foam, a polyurethane resin or the like is used which is obtained by curing solid rubber vulcanizate such as isoprene rubber, ethylene propylene rubber, silicone rubber, epichlorohydrin rubber, and acrylonitrile-butadiene rubber, and a liquid raw material such as a polyol by an isocyanate.
When it is required that the image forming device member has conductivity, for example, the image forming device member is adjusted to have a desired electrical resistance value by mixing a conductive material such as carbon black, and metal oxide, or adding an electrolyte. As the material configuring the polymer elastomer and the polymer foam, a polyurethane resin which is generated by using a polyol and a polyisocyanate as a main raw material is preferably used. The polyurethane resin has an advantage in that the polyurethane resin is able to impart conductivity by the conductive material and the electrolyte, is able to be used by dissolving the electrolyte in the liquid raw material, and is able to be a foamed body, as necessary.
The conductive polymer material including the polyurethane resin as a main constituent is manufactured by mixing a polyol component and a polyisocyanate component at a predetermined ratio, and by foaming and curing the mixture, as necessary. Then, the conductivity of the polyurethane resin is controlled by an added amount of the electrolyte or the like (for example, refer to Patent Document 1).